EFFECT OF MODERN RADIOTHERAPY ON PATIENTS WITH CARDIAC IMPLANTABLE ELECTRONIC DEVICES (CIEDs): A COMPREHENSIVE STUDY

During the last decades, cardiac implantable electronic device (CIED) therapy has become first line therapy for those who are at risk for life-threatening ventricular arrhythmias and those survived cardiac arrest. Therefore, there has be a continuous increase in the number of patients with CIEDs, especially in Europe and Italy. Also, the number of new cancer patients is expected to experience an increase of 53% for 2030. Because radiotherapy (RT) is considered as one of the main component of cancer treatment, approximately 50% of cancer patients will receive at least one course of RT during their treatment. Accordingly, over the last decades, there has been an ever-increasing growth in the number of cancer patients and comorbid cardiovascular disease using CIEDs. Since the publication of the American Association of Physicists in Medicine (AAPM)-TG34 report, as the earliest guideline published for the management of patients with CIEDs receiving general radiotherapy (RT) in 1994, technologies pertaining to all elements of the chain of RT have progressed. These developments, coupled with advancements in CIED technology, have led to a need for more research on this topic. Due to this fact, many studies have focused on the effect of radiotherapy on patients with CIEDs, and many aspects of this field have been investigated in the literature. However, with the widespread implementation of advanced RT technologies and techniques, the need to consider the different challenges of modern RT techniques when managing patients with CIEDs has arisen. The main goal of this comprehensive study is to investigate effects of modern radiotherapy on CIED patients. The thesis is divided in five chapters with an introductory chapter providing a very short explanation of CIED therapy and number of cancer patients with CIEDs. In the first part of the study, chapter2, a deep review of the literature and analysis study have been conducted. This review and analysis highlighted the available sparse information in the literature and ended up by posing questions for future research. In the second part of the research, chapter 3, the use of image-guided radiotherapy (IGRT) in patients with CIEDs was investigated. Accordingly, a multicenter dosimetry study to evaluate the imaging dose from Elekta XVI and Varian OBI kV-CBCT systems to cardiovascular implantable electronic devices (CIEDs) was carried out at four centers in the north of Italy, including university hospital of Trieste, Trento, Brescia, and Udine. The results of this study were applied to add new data in the literature and Associazione Italiana di Fisica Medica (aifm) working group. In the third part, chapter 4, the effect of a stereotactic body radiotherapy (SBRT) using flattening filter-free beams on implantable cardioverter-defibrillators (ICDs), as widespread modern modality for the treatment of cancer, was done. First, a retrospective analysis of patients with CIEDs who underwent radiosurgery SBRT and radiosurgery (SRS) at Peter MacCallum Cancer Centre (the largest cancer research group in Australia) between 2014 and 2018 was performed. This was complemented through a phantom study through a multidisciplinary study between medical physicists, radiation oncologists and electrophysiologists at the university of Trieste, Peter Mac and Royal Melbourne Hospital. The results of this study were used to update some of the policies applied to manage CIED patients undergoing SBRT/SRS at PeterMac. In the last part of this comprehensive study, chapter 5, a Monte Carlo (MC) study of out-of-field doses from an ELEKTA 6 and 15 MV photon beam in a homogeneous water phantom at depth of CIED and clinical depth was conducted. Correspondingly, a comparison between the MC results with MONACO treatment planning system (TPS), as a Monte Carlo-based TPS, and radiation dosimetry measurements was carried out to evaluate the accuracy of dose calculation outside the field, where a CIED is usually located.